The overall objective of the proposed research is the characterization of the kinetics of growth and dissolution of synthetic renal stone-forming minerals such as calcium oxalate hydrates, uric acid, calcium phosphate the urates. The highly reproducible procedure of seeded growth in stable supersaturated solutions, developed in our laboratory, will be used and a range of ionic strength, concentration and pH typical of those in urines will be studied in order to provide information about the nature of the solid phases formed in the stone-forming process. Emphasis will be placed on the elucidation of the factors controlling the formation of the mixed mineral solid phases (e.g., by epitaxy) found in renal stones; the influence of individual urine components on this process will be investigated. In parallel with these studies, specific surface area, scanning electron microscopic and electron microprobe investigations of the growing crystals will be made in order to relate crystal morphology to the kinetics of the growth process. A study will be made of the transformations which take place between the calcium oxalate hydrates and the influence of potential stone inhibitors upon the kinetics of their mineralization and dissolution. Kinetic studies of the precipitation of stone forming minerals upon representative stone samples will be made as a function of solution composition and in the presence of urine components.